Torque wrench and method of operating the same

Abstract

A torque wrench includes a hollow body, a clutch mechanism, a force-applying member, and driving arms. The clutch mechanism is mounted in the hollow body. The force-applying member is pivotally mounted in the hollow body. Each of driving arms has a coupling end is detachably mounted at the second end of the force-applying member and a driving end for driving a workpiece, wherein each of the driving arms is coaxial to the force-applying member when the coupling end thereof is mounted at the second end of the force-applying member, and wherein the interchangeable driving arms are different in length from each other.

What is claimed is: 
     
       1. A torque wrench, comprising:
 a hollow body comprising a handle and an elongate sleeve partially inserted in the handle; 
 a clutch mechanism mounted in the hollow body; 
 a force-applying member pivotally mounted in the hollow body, wherein the force-applying member has a first end against the clutch mechanism and a second end opposing to the first end; and 
 a plurality of interchangeable driving arms, each of interchangeable driving arms having a coupling end detachably mounted at the second end of the force-applying member and a driving end for driving a workpiece, wherein each of the interchangeable driving arms is coaxial to the force-applying member when the coupling end thereof is mounted at the second end of the force-applying member, and wherein the interchangeable driving arms are different in length from each other; 
 wherein a plurality of sets of scales are formed on the elongated sleeve each set of the scales corresponding to a separate one of the interchangeable driving arms and indicating a toque to be applied to the workpiece by said separate one of the interchangeable driving arms. 
 
     
     
       2. The torque wrench of  claim 1 , wherein the second end and the coupling end are bolted or engaged together. 
     
     
       3. The torque wrench of  claim 1 , wherein the clutch mechanism includes a spring, a load screw, and a plunger, the spring is compressed by the load screw and against the plunger, and the plunger is abutted against the first end. 
     
     
       4. The torque wrench of  claim 1  wherein the driving end of each interchangeable driving arm has a fixed lateral drive extension or a detachable driving unit. 
     
     
       5. The torque wrench of  claim 1 , wherein each of the interchangeable driving arms is a plurality of rods detachably assembled with each other. 
     
     
       6. The torque wrench of  claim 1 , wherein a plurality of indications corresponding respectively to the interchangeable driving arms are formed on the elongate sleeve, each of the indications being provided adjacent to one of the sets of the scales and providing a discernible indication of which of the interchangeable driving arms corresponds to said one of the set of the scales. 
     
     
       7. A method of operating a torque wrench, comprising the steps of:
 providing a torque wrench comprising a hollow body comprising a handle and an elongate sleeve partially inserted in the handle, a clutch mechanism mounted in the hollow body, a force-applying member pivotally mounted in the hollow body, wherein the force-applying member has a first end against the clutch mechanism and a second end opposing to the first end, and a plurality of interchangeable driving arms, each of interchangeable driving arms having a coupling end detachably mounted at the second end of the force-applying member and a driving end for driving a workpiece, wherein each of the interchangeable driving arms is coaxial to the force-applying member when the coupling end thereof is mounted at the second end of the force-applying member, and wherein the interchangeable driving arms are different in length from each other, wherein a plurality of sets of scales are formed on the elongated sleeve each set of the scales corresponding to a separate one of the interchangeable driving arms and indicating a toque to be applied to the workpiece by said separate one of the interchangeable driving arms; 
 mounting the clutch mechanism and the force-applying member in the hollow body; 
 mounting one of the interchangeable driving arms at the second end of the force-applying member, wherein the interchangeable driving arm mounted at the second end of the force-applying member is coaxial to the force-applying member; and 
 driving the workpiece by taking the overall length of the force-applying member and the interchangeable driving arm mounted at the second end of the force-applying member as a first moment arm. 
 
     
     
       8. A torque wrench for holding a socket, comprising:
 a hollow body comprising a handle and an elongate sleeve partially inserted in the handle; 
 a clutch mechanism mounted in the hollow body; 
 a force-applying member pivotally mounted in the hollow body, wherein the force-applying member has a first end against the clutch mechanism and a second end opposing to the first end; and 
 a plurality of interchangeable driving arms, each of interchangeable driving arms having a coupling end detachably mounted at the second end of the force-applying member and a driving end for holding the socket, wherein each of the interchangeable driving arms is coaxial to the force-applying member when the coupling end thereof is mounted at the second end of the force-applying member, and wherein the interchangeable driving arms are different in length from each other; 
 wherein a plurality of sets of scales are formed on the elongated sleeve each set of the scales corresponding to a separate one of the interchangeable driving arms and indicating a toque to be applied to the workpiece by said separate one of the interchangeable driving arms. 
 
     
     
       9. A method of operating a torque wrench, comprising the steps of:
 providing a torque wrench for holding a socket comprising a hollow body comprising a handle and an elongate sleeve partially inserted in the handle, a clutch mechanism mounted in the hollow body, a force-applying member pivotally mounted in the hollow body, wherein the force-applying member has a first end against the clutch mechanism and a second end opposing to the first end, and a plurality of interchangeable driving arms, each of interchangeable driving arms having a coupling end detachably mounted at the second end of the force-applying member and a driving end for holding the socket, wherein each of the interchangeable driving arms is coaxial to the force-applying member when the coupling end thereof is mounted at the second end of the force-applying member, and wherein the interchangeable driving arms are different in length from each other, wherein a plurality of sets of scales are formed on the elongated sleeve each set of the scales corresponding to a separate one of the interchangeable driving arms and indicating a toque to be applied to the workpiece by said separate one of the interchangeable driving arms; 
 mounting the clutch mechanism and the force-applying member in the hollow body; 
 mounting a driving unit at the second end of the force-applying member; 
 driving the workpiece by taking the length of the force-applying member as a second moment arm; 
 mounting one of the interchangeable driving arms at the driving unit, wherein the interchangeable driving arm mounted at the driving unit is coaxial to the force-applying member; and 
 driving the workpiece by taking the overall length of the force-applying member, the driving unit and the interchangeable driving arm mounted at the driving unit as a third moment arm.